Roof construction



Dec. 2, 1952 L. LINDQUIST ROOF CONSTRUCTION Filed Feb, 25, 1948 Patented Dec. 2, 1952 ROOF CONSTRUCTION Gustav Lennart Lindquist, Stockholm,Sweden Application February 25, 1948, Serial N0..10,810

InSweden January 19, 1945 Section .1,"Pu'blic Law 690, August 8, 1946 Paten'texpires January 19, 1965 6 Claims. (Cl. 108-45) This invention relates to roofs of concrete, porous concrete or similar materials covered with asphalted roofing felt or the like.

In an ordinary construction of such roofs the roofing felt is pasted directly to the underlying layer of concrete or .to an underlying heat insulating layer on the concrete .or to a supporting roof of slabs of porous concrete, e. g. slabs of materials known on the market as Siporex (reg.

trade-mark), Ytong (reg.-trade-mark) or similar materials. This construction has some drawbacks because during cold weather heated and moist inner air condenses under the roofing felt or in the upper portion of the heat insulating layer. On account of the remaining moisture Whichis confined to the space under the roofing felt the heat insulation is less good and in the winter the condensate freezes which may cause the insulating materials to be destroyed and the roofing felt to loosen from the underlying layer.

During warm weather the roofing felt prevents melted water from evaporating. Thus, the melted water remains and may cause formation of bubbles due to vaporization at those places where the roofing felt has loosened from the underlying layer with the risk of the waterproofing material getting untight.

The principal object of the present invention is to overcome the defects set forth above and to provide a roof from which moisture ascending from within the building into the concrete will readily beremov'ed. It has been discovered that by providing a ventilating layer on the concrete which layer permits the circulation of air and removes the moisture penetrating from below into the concrete, the difficulties heretofore presented in such structures are eliminated or diminished.

Another object is to provide a ventilating layer which will be of such a nature as to be easily applicable and as to be serviceable as a support for the outer roofing felt.

The invention will be more fully understood by reference to the accompanying figures of the drawing, which illustrate two practical embodiments of roofs from which moisture ascending 2 the supporting concrete slab of the roof and 2 indicates a heat insulating layer, for instance, of porous concrete, cellular concrete, cinder concrete or the like. On the 'heat insulating layer 2 there is arrangeda ventilating layer 3 according to the invention. This'layer is permeable to air and moisture and consists of a granulated relatively hard stone filler material, for instance, graniteor quartz gravel having a grainsizeof 8 to 16 mm. The filling material is spread evenly over the layer 2 and is applied by means of an adhesive, e. g. tar or asphalt, only lying as a thin surface on the filler grains and not preventing air and water from permeating the layer both perpendicularly to the plane of the layer and in its own plane between said grains. A waterproofing 4 consisting of asphalted roofing felt is pasted to the ventilating layer -3. A metal forms a water drip for condensate or melted water which flows away from the ventilating layer. A further sheet 6 is placed under the waterproofing 4 and carries rain water away from the roof.

By the ventilating layer the condensate which may have accumulated under the roofing felt will flow away. The removal of moisture ascending from within the building into the concrete which moisture, if same is allowed to remain there, will affect the insulating capacity, is accelerated by means of air circulating through the ventilating layer so that a'very good ventilation of the layer, as a whole, takes place. Thus, the advantage is gained that the protective capacity against loss of heatof the roofing is maintainedand the waterproofing is protected against damage due to formation of ice under the roofing felt.

The necessary thickness *of such a ventilating layer 'will be dependent on the slope of roof,

the distance between roof drains and'many other local factors. Generally, a thickness of 8 to 30 mm. seems to be sufiicient. The layer must not be too thick as in such case there is the risk that it may slide. Nor must it be too thinas it then may be easilyobstructed by tar or asphalt which is used when the roofing feltis pasted and which during hot weather may fiow down and 'fill the spaces of the stone "material. To prevent this it is suitable onthe top ofthe ventilating layer to make a superficial treatment, for instance by means of cement and a filler of ground stone or quartz or the like.

In Fig. 2 the supporting structure 8 of a gently sloping roof rests on brick walls '1. On the concrete slab there is arranged according to the invention a ventilating layer 9 containing a heat insulating slab Ill of wood fibre, corrugated paper material as Wellit (reg. trade-mark) or the like. Thus, in this case the ventilating layer is double, the thickness of the layer on each side of the heat insulating slab being about 25 mm. A waterproofing H of asphalted roofing felt is arranged outermost.

As in this case the room is substantially horizontal, the granulated filling material may be applied witihout use of any adhesive. Such a layer will be very efiective from the point of view of ventilation as there is no risk of the spaces between the grains of the filling material becoming obstructed, which to a certain degree may occur when using adhesive in excess. Nor is there any risk of the foundation under the ventilating layer becoming obstructed so that moisture can freely ascend therefrom and be removed through the ventilating layer.

Alternatively, the filling material in the ventilating layer on one side of the insulating slab It), e. g. on the upper side, may be applied by means of an adhesive.

A horizontal impregnated wooden rail 12 onto which another rail I3 is nailed is anchored in the concrete at the eaves. Suitably spaced notches M are made in the wooden rail [3, through which notches the ventilating layer communicates with the outer air. In Fig. 3 showing the rail I3 from below an embodiment of the notches M is illustrated. The roofing felt II extends down on the outside of the rail 13 which is bevelled on the top.

A roof drain I5 is arranged at the lowest point of the roof, which is insulated in known manner from the concrete slab 8 by means of a mat of glass wool or stone wool. Collars l1 extending from the drain are secured by means of asphalt 48 which is cast around them. A layer E9 of tow linen extends down into said asphalt.

The drain I5 is provided with twelve bores 26 having a diameter of 10 mm., through which bores the ventilating layer communicates with the outer air and through which condensate can fiow away.

When arranging the roof in conjunction with a wall, there is arranged an impregnated rail 2! with holes 22 corresponding to the holes I4 of the rail I3 at the eaves for carrying away moist air. The roofing felt ll extends on the outside of the rail 2| up to the holes 22. The rail 2! is attached to impregnated logs 23 which are em-. bedded in the wall, for instance, at every fourth brick. A screen 24 of galvanized sheet metal is arranged a distance above the rail 21.

If a layer of cement and a filler is applied to the ventilating layer a thin layer of fabric, e. g. gunny cloth, may preferably be inserted between said layer of cement and a filler and the ventilating layer.

What I claim is:

1. A roof comprising a foundation of concrete, a ventilating layer pervious to air and moisture and lying over the foundation and comprising a granulated relatively hard stone filling material laid upon the foundation, the grains of said filling material having a thin surface coating of adhesive not preventing air and water from permeating said ventilating layer in its own 4 plane between said grains, said ventilating layer being in communication with the outer air at the roof edge, and an overlying layer of water-' proofing material.

2. A roof comprising a foundation of concrete, a ventilating layer pervious to air and moisture and lying over the foundation and comprising a granulated relatively hard stone filling mate rial laid upon the foundation, the thickness of said ventilating layer being 8 to 30 mm., said ventilating layer being in communication with the outer air at the roof edge, and an overlying layer of water-proofing material.

3. A roof comprising a foundation of concrete, a ventilating layer pervious to air and moisture and lying over the foundation and comprising a granulated relatively hard stone filling material laid upon the foundation, said ventilating layer being in communication with the outer air at the roof edge, a thin tightening layer laid on the top of the ventilating layer, and an overlying layer of water-proofing material.

4. A roof comprising a foundation of concrete, a ventilating layer pervious to air and moisture and lying over the foundation and'comprising a granulated relatively hard stone filling material laid upon the foundation, at least one layer of heat insulating material being contained in the ventilating layer, said ventilating layer being in communication with the outer air at the roof edge, and an overlying layer of water-proofing material.

5. A roof comprising a foundation of concrete, a ventilating layer pervious to air and moisture and lying over the foundation and comprising a granulated relatively hard stone filling material upon the foundation, a communication between the ventilating layer and the outer air at the edges of the roof, and an overlying layer of water-proofing material.

6. A roof comprising a foundation of concrete, an insulating layer of porous concrete at the top of said foundation, a ventilating layer pervious to air and moisture and lying over said insulating layer and comprising granulated relatively hard stone filling material laid upon said insulating layer, the grains of said filling material having a thin surface coating of asphalt not preventing air and water from permeating said ventilating layer in its own plane between said grains, said ventilating layer being in communication with the outer air at the roof edge, a thin layer of fabric laid on said ventilating layer, a tightening layer of cement and a filler arranged on said layer of fabric, and an overlying layer of water-proofing roofing felt.

GUSTAV LENNART LINDQUIST.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,931,066 Eckert Oct. 1'7, 1933 2,192,458 Swenson Mar. 5, 1940 2,211,371 Faber Aug. 13, 1940 FOREIGN PATENTS Number Country Date 799,151 France 1936 

